To increase the chance of fertilization, several kinds of treatment including IUI, IVF, GIFT and ICSI are performed with sperm preparations composed of viable and motile sperms, free of seminal plasma and debris.
Under in vivo conditions, potentially fertile spermatozoa are separated from immotile spermatozoa, debris and seminal plasma in the female genital tract by active migration through the cervical mucus. During this process, not only progressively motile spermatozoa are selected, but male germ cells also undergo physiological changes called capcitation, which are fundamental prerequisites for the sperm's functional competence with regard to acrosome reaction. The introduction of assisted reproduction, especially of IVF, during the 1980's, led to the development of a wide range of different sperms separation methods. Following the development of the classical swim-up method by Mahadevan & Baker, more complicated techniques were developed to increase the number of motile spermatozoa even in severe anthological cases. On principle, these techniques can be differentiated in migration, density gradient centrifugation and filtration techniques. For all migration methods, the self-propelled movement of spermatozoa is an essential prerequisite, while for density gradient centrifugation and filtration techniques the methodology is based on a combination of the sperm cells' motility and their retention at phase borders and adherence to filtration matrices, respectively. The migration techniques can again be subdivided into swim-up, under-lay and migration-sedimentation methods. For density gradient centrifugation, separation media like Ficoll®, Nycodenz and Percoll® including the products (lxaPrep®, PureSperm®, Isolate®. SilSelect®) have recently been introduced to replace Percoll®. The filtration methods like glass wool filtration and filtration of spermatozoa on Sephadex beads and membranes are alternative techniques.
At present time, there is no ideal method for preparation of sperms for ART. The ideal sperms separation technique should (i) be quick, easy and cost-effective, (ii) isolate as much motile spermatozoa as possible, (iii) not cause sperm damage or non physiological alterations of the separated sperm cells, (iv) eliminate dead spermatozoa and other cells, including leukocytes and bacteria, (v) eliminate toxic or bioactive substances like decapacitation factors or reactive oxygen species (ROS), and (vi) allow processing of larger volumes of ejaculates. Since none of the methods available meets all these requirements, a variety of sperms separation techniques are mandatory in clinical practice to obtain an optimal yield of functionally competent spermatozoa for insemination purposes. Depending on the ejaculate quality, these methods have different efficiency and areas of use. In the conventional swim-up technique, functional spermatozoa can come into close cell-to-cell contact with defective sperm or leukocytes by centrifugation, thus causing massive oxidative damages of the sperm plasma membrane by ROS and consequently of sperm functions, therefore, the quality of the ejaculates has direct consequences on the choice of a sperm separation method.
Also Aitken and Clarkson have shown that centrifugal force generates the production of reactive oxygen species that may damage sperm and impair their fertility potential.
It has been reported that when sperms are put into a fluid flow, the motile sperms rapidly align themselves and swim upstream. Non-motile and sluggish sperms, along with other cellular components, are washed downstream away from the motile sperms. Cilia have been shown to be present in the endometrial cells of many mammals. Ciliary's currents in both the fallopian tubes and the uterus move in the same direction and extend towards the external os. One may expect that this flow act as a guide for sperms, leading sperm with the correct motility parameters towards the site of fertilization at the ampoule of the fallopian tubes. Secondly, this flow acts as a natural selection mechanism to optimize the quality of sperm able to reach the fertilization site.
Based on this phenomenon of the sperms the present invention has a number of advantages over conventional methods of preparing sperms and it seems that has all of the characteristics of an ideal method including but not limited to;                Not inducing any damage to the sperms, because the procedure does not require any use of chemicals or centrifuges.        Rapid and simple preparation process.        Physicians can use the module without the need for expensive laboratory equipment.        The use of the module in accordance with the invention not only serves to separate sperms, but also washes the sperms, thus eliminating the need for any centrifuge process.        
The present invention can be used not only for the separation of motile from non-motile sperms but can also be used with motile, morphologically normal sperms, to provide sperms suitable for ART and IUI procedures.